The present invention relates to an optical connection unit for the optically conducting connection of light conducting, receiving and/or emitting optical elements. The apparatus is further directed to the use of an optical connection unit of this kind in an optical network.
Optical connection units of this kind are always required when optical signals are to be transmitted from one place to another place. In this the optical signals can be data signals, i.e. signals carrying certain information to be evaluated, and in this in particular digital data signals. The optical signals can however also be simple light signals without a special information content, such as are used for example for lighting.
In order to be able to ensure as low an intensity loss in the transmission of the optical signals as possible, the optical coupling between the connection locations of different conduction sections which are present in the light transmission path must be designed as loss-free as possible. For this it is required that the cooperating coupling surfaces of two line sections which border on one another lie directly in contact, i.e. without a spacing.
In known connection units the corresponding optical elements, for example plugs and associated coupling, must either be manufactured with correspondingly high precision; or in each case the elements to be coupled to one another are drawn together by spring elements gripping on the respective housings of these elements in such a manner that the coupling surfaces of the two optical elements lie in contact with one another.
The first of these solutions has the disadvantage that it places high requirements on the manufacture of the parts used and is thus correspondingly expensive. Disadvantageous in the second solution given is that the coupling surfaces of the optical elements which lie in contact with one another can be moved apart for example through an inadvertent pulling at the light conductors counter to the spring force holding the elements together, through which the optical damping increases abruptly or, respectively, in the worst case the optical coupling is completely interrupted.
A further disadvantage consists in that for example in a connection of two or more light conductors via a common node element or in the connection of one or more light conductors to an emitter or receiver element for example via a mixer, i.e. an optical distributor or an optical collector unit, in each case separate spring elements must be provided in each case at all contact locations of the node element or the mixer respectively, at least however at its input and at its output side. Through this the costs for corresponding connection units are further increased.
An object of the invention is to design an optical connection unit of the initially named kind in such a manner that a simple and in this at the same time a reliable optical connection between light conducting, receiving and/or emitting optical elements is possible, with it being desirable that the damping of the optical connection remain a minimum even in the event of mechanical stressing.
In accordance with the invention this object is satisfied by an optical connection unit for the optically conducting connection of optical elements which conduct, receive and/or emit light comprising an optical transmission element which has at least one coupling surface for the optical coupling on at a coupling surface of one of the optical elements and which is designed as a spring element so that the coupling surface of the transmission element can be subjected to a bias force in the direction of the coupling surface of the optical element.
In accordance with the invention, thus, the optical transmission element is itself designed as a spring element so that the coupling surfaces of the optical transmission element and of the optical elements to be coupled to the optical connection unit are pressed against one another directly by the spring bias force which is produced by the optical transmission element. Because the coupling surface of the transmission element can be subjected to a bias force in the direction of the coupling surface of the optical element, it is ensured that in the event of an inadvertent pulling apart of the transmission element and the coupled on optical element, for example through a mechanical stressing, the coupling surface of the transmission element follows the movement of the optical element as a result of the innate bias tension of the transmission element so that a moving apart of the two coupling surfaces, which lie in contact with one another, is prevented. An increase in the damping between the optical elements which are connected to one another or an interruption of the optical connection is thus reliably prevented, at least up to a certain maximum displacement of the coupling surface of the optical element.
In accordance with a further preferred embodiment of the invention the transmission element has at least two coupling surfaces for the coupling on at the optical elements. In this way for example two or more light conductors can be very simply connected to one another. It is in principle however also possible that the transmission element has only one specially designed coupling surface for the coupling on for example at a light emitting signal source and that the light which is coupled into the transmission element in this way is conducted via a light conductor which is designed in a single piece with the connection unit to a destination and is for example radiated off there for the display of a certain information. It is furthermore possible that the transmission element has more than two coupling surfaces so that a large number of optical elements can be connected to one another via a single optical connection unit.
In accordance with a further preferred embodiment of the invention the transmission element comprises a flexible, in particular elastic light conductor, in particular a plastic or glass fiber cable. In this the coupling surfaces are advantageously formed by the end surfaces of the light conductor.
In this way a very simple and economical embodiment of an optical connection unit is possible, with both end surfaces of the light conductor being used when the optical connection unit is used for the connection of a plurality of optical elements. It is however also possible that the light conductor which forms the transmission element is merely the end of a longer light conductor so that the optical connection unit is formed in a single piece with this longer light conductor. In this case a further optical element can be connected directly to the longer light conductor via the integrally formed optical connection unit. In the execution of the light conductor of an elastic material the spring effect can be achieved directly through deformation, in particular through a lateral bending out of the light conductor.
In accordance with a further embodiment of the invention elastic elements, in particular elastic material are provided laterally to the light conductor through which the light conductor is held substantially in a predetermined shape. The optical transmission element is in this case formed by the combination of the light conductor and the elastic elements. The light conductor is preferably at least region-wise surrounded by elastic material. In this embodiment the execution of the transmission element as a spring element is achieved through the additional elastic elements. The light conductor is embedded with respect to the elastic elements or, respectively, in the elastic material, or at least surrounded at a predetermined distance by the latter, in such a manner that a lateral deformation, for example a bending, of the light conductor also produces a deformation of the elastic elements or, respectively, of the elastic material. Through the thus arising restoring forces within the elastic elements or, respectively, of the elastic material it is ensured that the coupling surface or the coupling surfaces respectively of the light conductor are subjected to a bias force in the direction of their respective initial position, which corresponds to the relaxed position. In principle it is also possible to manufacture the light conductor of an elastic material as well so that the functionality of a spring element is achieved through a combination of an elastic light conductor with an elastic material surrounding the latter.
The light conductor is preferably arranged in a housing, with at least one section, in particular an end of the light conductor, being led to the outside through an opening which is formed in the housing, and with this section of the light conductor which protrudes to the outside being moved in the direction towards the interior of the housing when the transmission element is subjected to a bias force. Preferably two sections, in particular the two ends of the light conductor, are led to the outside through the housing wall and are movable.
Through this embodiment it is achieved that in the relaxed state the end section or the end sections of the light conductor respectively which carry the coupling surface protrude to a maximum extent out of the housing so that the coupling surface of the optical element which is to be connected with the connection unit can be placed on the coupling surface which protrudes from the housing. If the optical elements are moved further in the direction of the housing after the contacting has been completed, then the light conductor is deformed within the housing against the spring bias force so that the respective coupling surfaces lie in contact with one another under the action of a bias force. Through this a reliable and damping-poor connection is ensured. The bias force of the transmission element is thus automatically produced in this embodiment by the application and the fixing of the respective optical element at the optical connection unit.
In accordance with a further advantageous embodiment of the invention an actuation member is provided at the housing for the biasing of the transmission element. In this embodiment it is thus possible to effect the biasing of the transmission element for example through the bending of the light conductor via a push-button which is provided at the housing and which acts laterally on the light conductor. This can for example be appropriate when the optical connection unit is to be inserted into a larger constructional unit and the ends of the light conductor which protrude out of the housing in the relaxed state would be disturbing during the insertion of the optical connection unit into the constructional unit.
For example an opto-electrical element which is fixed at a conductor plate and, at a certain distance from it, the end of a single light conductor or a light conductor bundle which is fastened to the constructional unit can be provided in the constructional unit which are to be connected via an optical connection unit which is designed in accordance with the invention. Prior to the insertion of the connection unit the optical transmission element can be subjected to a bias force through the actuation of the push-button, with the ends of the light conductor being retracted. In this state the connection unit can be inserted into the region between the opto-electrical element and the end of the light conductor or of the light conductor bundle respectively, whereupon the push-button is released. As a result of the bias force of the optical transmission element its ends are displaced outwardly so that they come to lie in contact under stress at the coupling surfaces of the opto-electrical element and of the light conductor or of the light conductor bundle respectively.
Further advantageous embodiments of the invention are set forth in the subordinate claims.